Double disc liquid applicator for tow and method of using



y 21, 1968 J. R. GODWIN ETAL 3,384,507

DOUBLE DISC LIQUID APPLICATOR FOR TOW AND METHOD OF USING Filed April 6, 1964 United States Patent 3,384,507 DOUBLE DEC LEQUID APPLICATOR FOR TOW AND METHOD OF USING Joseph R. Godwin and George A. Watson, Charlotte, N.C., assignors to Celanese Corporation of America, New York, N.Y., a corporation of Delaware Filed Apr. 6, 1964, Ser. No. 357,651 Claims. (Cl. 117105.3)

ABSTRACT OF THE DISCLOSURE A method and apparatus for the treatment of an elongate fibrous base member, especially a tow comprising several thousand crimped synthetic filaments, with a fluid form material such as a plasticizer for said filaments by centrifugally projecting said fluid form material from at least two disc-like members disposed in upwardly canted transverse planes across a vertical tow path defined, for example, between tow opening and air spreading equipment in a cigarette filter making operation.

This invention relates to the treatment of filamentary and other fibrous materials in order to impart certain desired or selected properties thereto and is more particularly concerned with the production of filter-rod stock for use in the manufacture of filter-tip cigarettes.

Filters for cigarettes may be comprised of any of numerous substances in any of a variety of forms. Usually, however, a filamentary material such as any of various synthetic fibers or another type of fibrous material such as crepe paper is utilized for this purpose. A widely prefer-red cigarette filter is formed of a multiplicity of filaments arranged in essentially longitudinal alignment, with substantially all of such filaments extending continuously from one end of the filter to the other.

In the production of a filter of this latter type, a tow or bundle of upward of several thousand substantially longitudinally aligned continuous filaments, preferably already suitably crimped, is passed through one or more devices that serve essentially to open up the advancing tow. The result is that the tow assumes the appearance more or less of a continuous band or web of varyingly increased Width. The many different arrangements that have been proposed to accomplish this objective range from those which ordinarily do little more than flatten, Widen, and/or smooth out the tow to those which also separate the filaments as necessary to bring the same more nearly into longitudinal alignment and/or to effect deregistration of the wings in adjacent filaments.

The resulting opened, spread tow may then be passed without any further treatment essentially directly to the ga-rniture of a filter rodmaker, wherein it is condensed to provide a continuous filter-rod stock having a crosssectional area corresponding to that of the filter-tip cigarettes to be produced. customarily, the desired filter tips are obtained by appropriately cutting or severing such continuous filter-rod stock as it is formed.

Alternatively, prior to being condensed to form the continuous filter-rod stock, the opened tow may be treated with a selected additive material in order to impart a desired property or effect thereto. Such additive material may be in liquid form, that is, a liquid per se or a suspension or solution of a solid in a liquid vehicle; or it may be a solid. Illustrative types of liquiform additive materials comprise plasticizers such as glycerol triacetate( triacetin) and triethyl citrate, lubricants such as light mineral oil and diethylene glycol, and antistatic agents such as a mixture of magnesium chloride in water and diethylene glycol. A typical solid additive material comprises a fluidizable "ice particulate absorptive substance such as carbon black or powdered charcoal.

Whether such fluidiform treating material exists in the liquid form or the solid form, a number of procedures is available for applying the same to the advancing tow. A liquiform treating material such as a plasticizer or other filament-bonding agent, for example, is customarily discharged through appropriately arranged and designed spray nozzles or similar spray-forming devices onto the opened tow as it is longitudinally advanced past such nozzles. Alternatively, the opened tow may be longitudinally advanced in contact with one or more rolls that have been coated with such liquiform treating material and that thereby transfer such treating material to the opened tow.

If a fluidizable particulate solid comprises the treating material, it may also be suitably sprayed onto the longitudinally advancing tow. A suction-creating device may be used in this connection, with the view of obtaining an improved distribution of the particulate solid among the tow filaments, where such spraying is conducted in a chamber or other confined space through which the opened tow is longitudinally advanced. It is also possible, of course, to effect a sort of impregnation of the opened tow with the particulate solid by longitudinally passing such tow through a batch of the solid particles.

Regardless of the purpose for which the fluidiform treating material is applied to the opened tow, it will be evident that as the distribution of such treating material on and/or within the advancing tow can be made more nearly uniform, the more closely will the desired objective be achieved. Simple as such goal may seem of attainment, unfortunately in practice it has been more or less elusive.

It would seem that a substantially uniform application of a fluidiform treating material to alongitudinally advancing tow or similar continuous filamentary body or base member could be quite readily accomplished by simply spraying the treating material onto the tow. That such is not the case, however, becomes only too obvious just from a consideration of the number of widely different techniques for spraying or similarly applying the treating material to the advancing tow in the hope that as nearly uniform a distribution of such treating material as possible will result. Although the spraying or other application of a treating material to both sides of an advancing opened tow has been specifically proposed, the usual result is that only localized portions of the tow exhibit any substantial uniformity of distribution of the treating material on and within the filaments.

The provision of a system that will continuously accomplish substantially uniform application of a treating material throughout its length to a longitudinally advancing tow or similar elongated fibrous or filamentary base member is thus greatly to be desired.

It is a primary object of the present invention, accordingly, to provide an improved process of and apparatus for treating an elongated fibrous or filamentary base member with a fiuidiform material in such a manner that the indicated disadvantages are effectively avoided.

It is a further primary object of the present invention to achieve the aforesaid object in a system wherein said elongated fibrous or filamentary base member travels in a primarily vertical direction during said treating thereof with a fiuidiform material, whereby there is a substantial saving of space.

A further object of this invention is to provide a method of an apparatus for specifically utilizing such development in the conversion of a tow to cigarette filter-rod stock.

Other objects and further advantages of the invention FIG. 2 is a side elevation of a downstream modification.

of the aforesaid embodiment of the apparatus of the present invention.

In FIG. 1, tow 13 passes the nip of each of two sets of rolls (11, 12) and (11 12), rolls 11 and 11' being rubber, non-threaded rolls and rolls 12 and 12' being steel, threaded rolls; each rubber, non-threaded roll is a driven roll with a one-inch thick rubber covering of approximately 70 Shore Durometer hardness (A Scale) and each steel, threaded roll is of stainless steel and springloaded against its companion rubber roll; tow 13 then passes between the applicator chambers .14 and 14', which are closed on three sides and open on the fourth side which faces tow 13; each applicator chamber contains a disc, 15' and 15, respectively, at an angle no greater than about 45 from the horizontal; each disc may be of any of the constructions indicated in commonly assigned copending application Ser. No. 216,894, filed Aug. 14, 1962 now abandoned; discs .15 and 15' are driven by motors 16 and 16, respectively, each of which is connected to a disc by a drive shaft; through feed nozzles 17 and 17 is fed the fiuidiform material to be applied to the tow; the fiuidiform material gravitates to the discs, which are rotating, and is projected outwardly from the peripheries of the discs in the form of sheets of droplets which uniformly contact the tow surfaces; tow 13 then passes through air spreaderfeeder which comprises a drum 18 through the axis of which is fed compressed air which passes through a longitudinal slot across the face of the drum and parallel to its axis and which slot is located near the downstream terminus of guide 19, which guide is as Wide as the drum; the air spreader-feeder guides, flattens, and opens the tow; tow 13 then passes to garniture 20 of a conventional filterrodmaking machine.

In FIG. 2, there is illustrated a modification of the above-described apparatus wherein an endless-belt-fed oven 21 is disposed between the air spreader-feeder and the garniture whereby the fiuidiform material-containing tow is heated to effect, for example, bonding of the filaments of the tow.

The method and apparatus of the present invention represents a distinct improvement over the method and apparatus of copending application Ser. No. 216,894, filed Aug. 14, 1962. While the aforesaid copending application does state that the therein disclosed methods and apparatuses achieve uniform application of the fiuidiform material, this is only relative to conventional spraying, as directly with a nozzle. Thus, the present application rep resents still a further improvement.

Not to be minimized is the fact that the vertical arrangement of the tow opening rolls permits the tow bale to be positioned directly adjacent the filter rodmake'r with attendant saving in floor space. This is especially important when installing the tow opening rolls in plants where the filter rodmakers are in fixed positions so that there is but limited space therebetween for installation or positioning of further equipment or tow bales.

The plane in which each disc is to rotate may vary from the horizontal, preferably not more than about from the horizontal and desirably not more than about or more. In practice, it has been found to be especially suitable to mount each disc to rotate substantially in the horizontal plane. In general, the greater the angle between the plane of rotation of the discs and the horizontal plane, the broader the arc in which the droplets travel and the larger and more unwieldy the space requirements for the applicator chambers. In an embodiment illustrated more clearly in FIGURE 1, the plane of rotation of the disc members are each canted upwardly at the edge adjacent the tow.

Preferably, the tow is drawn between the applicator chambers at a predetermined speed between about 50 and 250 meters per minute. At the same time, the applicator discs are rotated at a speed between about 1000 and 4000 revolutions per minute while the liquid plasticizer is being fed to each disc at a rate of about 10 to 300 grams per minute.

The discs and complementary feed means may be of any of the constructions described in detail in abovementioned copending application Ser. No. 216,894.

The above mentioned system of cooperating threaded and unthreaded rolls and the above-mentioned garniture may operate in the modes and may be of any of the constructions described in detail in commonly assigned copending application Ser. No. 263,855, filed Mar. 8, 1963, now Patent No. 3,329,543. Similarly, the roll system and garniture may be juxtaposed and cooperatively function in the modes described in detail in said copending application.

It is to be understood that the foregoing description is not intended to limit the scope of the present invention and that many modifications thereof may be routinely obvious to the average worker skilled in the art.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of making cigarette filter stock from a tow composed of a multiplicity of substantially longitudinally aligned crimped continuous filaments, the crimps of adjacent filaments being in registry, comprising opening the tow and thereby deregistering the crimps of adjacent filaments by longitudinally advancing said tow along a path extending vertically downwardly through the nip of at least one pair of rolls, at least one roll of at least one of said pair of rolls having a threaded surface, further advancing said tow in opened form along said vertical path through a treating zone including at least two rotatable disc-like members adapted to centrifu gally project a fluid form material in transverse planes across said tow up to 45 from the horizontal; and thereafter condensing the longitudinally advancing treated open tow to form a continuous filter-rod stock.

2. The method of claim 1, wherein said fluid form material is a plasticizer for said filamentary tow.

3. A method according to claim 1, which includes directing air under pressure against the longitudinally advancing treated opened tow to effect further spreading of the same prior to condensing such treated tow to form the continuous filter-rod stock.

4. A process according to claim 1, in which the weblike base member is composed of a multiplicity of continuous cellulose acetate filaments, and the fluid form material comprises a liquiform agent for bonding such cellulose acetate filaments.

5. A process according to claim 2, in which the weblike base member is longitudinally advanced at a rate of about 50 to 250 meters per minute, the bonding agent is fed at a rate of about 20 to about 700 grams per minute to each distributing surface, and the two distributing surfaces are each rotated at a speed of about 1000 to about 4000 revolutions per minute.

6. A process according to claim 2, which includes subsequently heating the treated Web-like base member to effect further bonding of the cellulose acetate filaments to the extent desired.

7. In a method of making a cigarette filter stock from a tow composed of a multiplicity of substantially longiangles up to about 45 to the horizontal while passing said tow downwardly through said treating zone.

8. The method of claim 7, also including the further improvement wherein said fluid form material is a fluidizable particulate solid.

9. A method according to claim 7, which includes directing air under pressure against the longitudinally advancing treated opened tow to effect further spreading of the same prior to condensing such treated tow to form the continuous filter-rod stock.

10. Apparatus for making cigarette filter-rod stock from a tow composed of a multiplicity of substantially longitudinally aligned continuous filaments which com-prises means to longitudinally advance the tow along a path extending vertically downwardly through a treating zone; means disposed in said zone for opening said tow, said means including at least one pair of rolls defining a nip therebetween lying on said path, at least one of said rolls of at least one of said pair of rolls having a threaded surface; means located downstream of said tow opening rolls for applying a fluid form material to said opened tow, said means including at least two rotatable disc members disposed on opposite faces of said tow having planes of rotation laterally transverse to said tow and being inclined upwardly toward said tow at an angle up to about 45 from the horizontal; means to feed a fluid form material to said disc members; and means to rotate said disc members causing said fluid form material to be centrifugally discharged therefrom into contact with the opposite faces of said tow.

11. The apparatus of claim 10, further including means, downstream of said fluid form application means, to direct air under pressure against the longitudinally advanced treated opened tow in order to effect further spreading of the same.

12. Apparatus according to claim 10, in which each rotatable member is so arranged that the angle between the upwardly extending plane including the discharge edge of its distributing surface and the horizontal is about 30 at the most. 1

13. In a method of making a cigarette fi-lter stock from a tow composed of a multiplicity of substantially longitudinally aligned crimped continuous filaments comprising opening and deregistering the crimp in said tow and passing the tow through a treating zone comprising members centrifugally projecting a fluid form material across the tow path, the improvement comprising projecting as said fluid form material a fluidizable, particulate solid across said tow while passing said tow through said treating zone.

14. A method according to claim 13, in which the particulate solid additive comprises powdered carbon.

15. A method according to claim 14, in which the powdered carbon is selected from the group consisting of carbon black and powdered charcoal.

References Cited UNITED STATES PATENTS Re. 24,923 1/1961 Holt 118-325 X 1,946,831 2/1934 Bracewell 117-104 X 2,584,973 2/1952 Andermatt 239222.11 2,643,636 6/1953 Bauer 118316 2,775,792 1/1957 Beardsell et al. 118316 X 2,850,322 9/1958 Ingram 239222 2,865,324 12/1958 Stein 117-105.3 X 2,986,338 5/1961 Foster 239222 3,133,702 5/ 1964 Stelchek 239214 X 3,226,773 1/1966 Paliyenko 117 -104 X ALFRED L. LEAVITI, Primary Examiner.

I. H. NEWSOME, Assistant Examiner. 

